1. Technical Field
Various embodiments described herein relate to a semiconductor integrated circuit and, more particularly, to a semiconductor memory apparatus and a probe test control circuit for the semiconductor memory apparatus.
2. Related Art
As the size of semiconductor memory apparatuses decreases, memory cells are fabricated in the form of bulb ring gate (BRG) for circuits smaller than 66 nm. Presently, the BRG process is being used to circuits as small as 55 nm. In this BRG process, a leakage current between an enabled wordline and an adjacent wordline may increase. Consequently, there may be a need for conducting a test to verify whether or not there is any defect caused by the leakage current.
In the past, a wordline test was performed by enabling each wordline one by one, thereby, requiring a great deal of testing time.
To solve this problem, a method of performing the test by enabling one sub-wordline per 4 sub-wordlines was proposed. However, with recent trends toward making high capacity semiconductor memory apparatuses, even though ¼ sub-wordlines were enabled, the total number of sub-wordlines that must be enabled for a test increases inevitably. Due to this increase, the equipments that support the enabling operations during tests may lack sufficient, current driving capability thereby making it difficult to perform the test.
In order to overcome the above-mentioned problems, researchers have used a method in which the testing is performed by enabling a plurality of wordlines on a bank-by-bank or mat-by-mat basis (i.e., in the unit of bank or mat instead of activating all banks) at a package level.
In general, a mobile memory apparatus is provided at a bear chip state. Whether the memory apparatus at a bear chip state has a defect is verified by performing a wafer burn-in test. Moreover, a probe test is performed to verify whether there is a defect in writing and reading operations.
When performing a probe test on a mobile memory apparatus, however, the test mode is fixed such that all of the banks are activated during the test, making it impossible to perform the test on a bank-by-bank or mat-by-mat basis. Consequently, high-capacity mobile memory apparatuses, for example, require testing equipments having enhanced current driving capability. Therefore, high-capacity mobile memory apparatuses, for example, require testing equipments having high-performance current driving capability, thereby causing a cost increase for performing the test.